The scope of the present invention is that of casings for telescoped-type munitions.
Patent FR2679991 features a telescoped-type munition having a casing composed of plastic material, blocked at each end by a plug, also made of plastic material.
Choosing plastic material for the casing makes it easier to unload after firing. In fact the plastic casing does not present any residual radial deformation.
However, the problem arises of the mechanical resistance of the plugs under firing, the plugs also acting as a seal for the propellent gases.
Patent FR2679991 proposes providing metal reinforcing structure for the part of the plugs situated to the outside of the casing envelope. This reinforcing structure is composed of a ring which may be completed by a base plate.
However such reinforcing structure proves to be insufficient to deal with the pressure build-up of the propellent gases generated during firing. A plastic flow of the constituent material of the plugs can be observed, in that case, between the envelope and the reinforcing structure, this material thereafter forming a small wad likely to make unloading the casing more difficult.
Moreover, regarding the front plug, material constituting the plug has been torn off by the projectile.